Very nice. I recommend using looking into a different method of scaling spites. After effects default method makes a blurry edge when enlarging sprites. Tip: to achieve nearest neighbor scaling in after effects, use a plugin called "magnify" under the distort menu. This plugin gives you control over the scaling mode.

The basic concept is more stale than last century's bagel bin, the execution fresh. The animation is much better suited to Flash, where it shouldn't suffer from the same choppiness that keeps this from being easy on the eyes.